Plaster board having hard and soft portions



.Fuiy 29, 1924- J. K. SHAW PLASTIC 1R BOARD HAVING HARD AND SOFTPORTIONS Filed March 26. 1920 2 Sheets-Sheet 1 July 29, 1924. 1,503.2

J. K. SHAW PLASTER BOARD HAVING HARD "AND SOFT PORTIONS Filed March 26,1920 2 Sheets-Sheet 2 Patented uly 29, 1924.

it S A PATENT FFHOE.

JOHN K. SI-IAW, O'F MINNEAPOLIS, MINNESOTA, ASSIGNOR To C. F. DAHLBERG,OF

ST. PAUL, MINNESOTA.

PLASTER BOARD HAVING HARD AND SOFT PORTIONS.

Application filed March 26, 1920. Serial No. 368,994.

To all whom it may concern:

'Be it known that 1, JOHN K. SHAW, a citizen of the United States,residing at Minneapolis, in the county of Hennepin and State ofMinnesota,haveinvented certain new. and useful Improvements in PlasterBoard Having Hard and Soft Portions; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

This invention relates to a plaster board having hard and soft portionsand composed of interlaced fibres. It has for its object to provide aboard of this character which will be more efiicient in action and lessexpensive to manufacture than those heretofore proposed. I

With these and other objects in view the invention consists in the novelparts and parts constituting the combinations of board, all as will bemore fully hereinafter disclosed and particularly pointed out in theclaims.

Referring to the accompanying drawings forming a part of thisspecification in which like numerals designatelike parts "in all theviews v Figure 1 is a diagrammatic sectional view of an apparatussuitable for interlacing the fibres in accordance with this invention;

Figure 2 is a diagrammatic view illustrating the disposition of theindividual fibres 13 during the interlacing operation and beforereaching the traveling surface;

Figure 3 is a view similar to Figure 2 illustrating the action of thetraveling surface upon the individual fibres; and

Figure 4 is a diagrammatic sectional view of a plaster board made inaccordance with this invention.

In order that the character of this board may be the more readilydistinguished from the somewhat similar prior boards made of paper,fibre and other substances it is said: This board is composed ofdifferent layers of interlaced fibres, one of which layers is a hardrelatively unyielding and relatively very strong layer, which serves togive rigidity and strength to the board as a whole.

But its unyielding nature renders it unsuitable for the composition ofthe entire board owing to the strains produced by the setting of theplaster, and which requires a yielding material to accommodate the same.Therefore I provide one or more layers of fibres interlaced with saidfirst mentioned fibres and with each other, which layers are of a softor yielding nature and thus accommodate said strains. It has beenproposed heretofore to provide fibre board with felted fibres, but suchboards were made of the same kind of fibres, throughout, usually woodfibres; their felted relations did not involve the pronouncedinterlacing of the fibres that are possessed by this board, andtherefore their strength has been found to be very inferior to this saidnew board. Other inventive differences between this board and the priorboards can be best brought out by a disclosure of the process of makingthis board which will be understood from the following.

1 indicates any suitable tank for holding the water and fibres, 2 thebottom of said tank, 3 an inclined false bottom located above the bottom2, t a roll or drum near the lower end of said false bottom 3,5 aplurality of supporting rolls, 6 a guide and compression roll adjustableon the slide, or other movable means 7 8 a guide roll similar to theroll 1, and 9 a guide and tensioning roll adjustable on the means 10.Passing over the rolls just mentioned is the endless foraminous belt orsurface 11, conveniently made of wire cloth, and having the oppositelymoving portions or runs 12 and Between the runs 12 and 13 is located thewater outlet 15, provided with the controlling means or gate 16 whichmay be suitably manipulated as by the handle or other device 17.

Coacting with the foraminous surface or belt 11, and in close proximitythereto as regards one portion thereof, is the foraminous belt 18,passing over and around the series of guide rolls 19, 20, 21, 22, 23 and24. Said belt 18 also passes over thecompression and guide roll 25coacting with the compression roll 6, and adjustably mounted on themovable means 26. 27 represents a tension and guide roll, adjustablymounted on the means 28, and 29 an outlet for the Water passing throughthe belt 18, controlled by the gate 30 and adjustable through the handle31. 32 and 33 represent suitable water seals made of flexible materialfor the belts 11 and 18 respectively.

35 represents a channel-or passagefor water and fibres which may bemaintained at any desired hydrostatic head 36, 37Ian space 43 from therest of the tank, 45 rep-v resents a third channel for water and fibreshaving a head 46, 47 an opening into the tank space 48, and 49 apartition coacting with the partition 44 'to segregate said space 48from the remainder of the. tank.

The foregoing construction is, or may be,

substantially the same as that disclosed in my copendingapplication,Serial Number 368,990, filed March 26, 1920, and entitled Process of andapparatus for making fibre boards.

The operation of this machine understood from what follows:

It is preferred to use long bagasse fibres but of course fibres of anyusual length may be employed. Said fibres by reason of the direction offlow of the water through the belt 11, or surface 13, will bebrou htinto positions more or less. parallel to eadhother, and more orlessperpendicular to the line of travel of the surface 13, while at thesame time allof said fibres will occupy positions more or less staggeredwith relation to their neighbors as shown. Accordingly a largepercentage of the forward ends 61 of said fibres will first contact withsaid surface 13, and will be carried along by the belt from thepositions shown in Figure 2 to those shown in Figure 3, wherein the rearends 62 of said fibres are illustrated as having lagged behind the frontends 61, in the water, so that the front row of said fibres have assumeda somewhat curved or bent shape. The second row, or those fibres 63immediately following, and which have not reached the surface 13, buthave reached the rear ends'62 of the fibres 60, are now forced by theoncoming water to contact at their forward ends against the said curvedfibres' 60. And as said fibres 63, originally, due to their parallelpositions as shown in Figure '3, were more or less staggered orinterlaced with the fibres before the latter became curved, it isevident that this inter? lacing or entangling action between the fibres60 and 63 will be enhanced or inwill be It results from the interlacedor staggered with the fibres 63 will become intime'curved' and entangledwith the fibres 60 and 63 that have preceded said-fibres 64. It thusresults that owing to the floating of the fibres into parallel,

interlaced or staggered positions, and in a direction transverse to thetraveling surface 13, the entanglement of the fibres is continuousbetween successive'rows, and the pressure of the water causes the wholeto be very loosely assembled in their interlaced positions on-saidsurface, thus forming an open mass of fibres more compact next'to thewire than away from it, which mass is carried through the opening 76into the space 43, with one ormore partially curved and partiallyentangled layers similar to the fibres 60 and 63 clinging to it.

In said space 43, other fibres similar to the fibres 64 becomeinterlaced and entangled with the layers onthe belt, and the process ofentanglement and massing proceeds as before. In the mean time layers offibres in all respects similar to the layers 60, 63 and 64 areinterlaced, entangled and massed on the traveling belt 18 from the space48. This second mass of fibres are carried through the opening 71 by thebelt 18 in a condition similar to the first mentioned mass thatpassesthe opening 70, and the fibres in the. space 43 interlace, andbecome entangled with said second mass in a manner similar to thatdescribed in connection with said first "mentioned mass. The result is,owing to. the parallel and staggered relations of the fibres in thespace 43, they con stitute a third massof fibres which areinterlaced-and entangled with each other, as well as with ea :h of saidfirst named masses.

The action of the smoothly flowing water in separating and renderingparallel the oncoming fibres is in marked contrast with the stirring oragitating action of the water in prior processes, and the .difi'erenceresults in a great difference inthe strengths ofthe boards produced. 7

As a result of the foregoing entanglements of the various fibres andthe. motionof the surfaces 13 and 18, the mass offibres thereforeresides'not only in being able to thus positively interlace, orentangle, the.

fibres in the body of the sheet, but also in being able 'to vary thekind, size, or class, of fibres in different portions of the sheet.Thatis to say, I may feed to the channel 35, one ,kind of fibres, and Imay feed to the channel 45, the same class of fibres as are fedto thechannel 35, or I may feed a totally different class of fibres. In otherwords-I may provide as many channels 35,

40 and 45, as there are different characters of fibres in the finishedboard, and I may place in the first channel 35 and in the last channel45 any character of fibres I desire, whereupon the finished board willbe provided with an outer layer 77 corresponding to the fibres that arefed to the channel 35, with another outer layer 78 corresponding to thefibres that are fed to the channel 45, and with one or more intermediatelayers 79 corresponding to the character of the fibres which are fed tothe channel 40 and to any other channels which may be locatedintermediate of the channels and 45.

But the important feature to be emphasized in this invention is the factthat no matter how many kinds of fibres or how many layers of fibresthat are present in the finished board, the fibres of each layer will beinterlaced or entangled with the fibres of its adjacent layer, so thatthe board will not consist of separate and distinct layers somewhat likethe leaves of a book, that can be peeled off, but its body will consistof fibres that are firmly interwoven, and its outer layers will befirmly interwoven with said body portion.

The interlacing process is facilitated by the fact that the openings 37,42 and 47 are of a less area than are the spaces 38, 43 and 48 intowhich the fibres are led. In other words the fibres must pass throughthe opening in a comparatively close relation to each other, and t eyare then immediately released into a wider space, whereupon theynaturally pass along with the non-agitated water while spreading out andassuming the parallel relations indicated in Figure 2.

In order to produce a stronger board I further prefer to permit a verylarge proportion of the water, say 90% of the same to escape through theopening 15, while a very much smaller proportion, say 10% escapesthrough the opening 29. The gates 16 and 30 are conveniently manipulatedto effect this result, and by so proportioning the water may be enabledto maintain the proper steady flows through the. surfaces 13 and 18 toproduce the desired result. But of course the proportions of water thatescape through the two openings mentioned may be widely varied accordingto the results .sought in the finished boardl' I The rolls 6 and 25 arereadily adjusted 'by the means illustrated to produce any desiredcompression in the o enings 75 between said rolls, so that the bre boardmay be given any desired degree of porosity. In fact, by usingrelatively large fibres in the channel 40, and relatively fine fibres inthe channels 35 and 45, I am enabled to control the air spaces in thebody of the board, and thereby to control its heat-ipsulating qualities.

6 The heads 36,41 and 4c of the liquid in board.

the channels 35, 40 and 45 are so maintained liquid in the lastmentioned spaces are main-' tained as nearly equal as possible, and thusa minimum tendency of the fibres to fail to interlace is secured.

In order to produce the board of this invention I preferto treat 1 thefibres in the channel 35 with any suitable waterproofing solution toprevent the caustic action of the plasterthat is to be later applied tothe surface 77 from injuriously affecting the finished board. In thechannel 45 I may introduce any suitable hardening solution that willgive strength to, and harden the surface 78, so that the finished boardwill be yielding and more or less soft on its interior and strong andhard on its surface 78. A suitable Water repellent is found in the wellknown mixture of rosin and aluminum sul such hardening solution to thechannel 45,

I am enabled to produce a hard, strong and relative] smooth surface 78on the finished 11 some cases, I prefer to apply to the surface 78whether treated with said bagasse fibre solution, or not, a thin coatingof a cementitious material, such as Portland cement, or one of theoxy-chloride cements, such as magnesium oxy-chloride, and thus produce amore pronounced hardening of sald surface.

In 'all cases whether this board is provided with grooves or not it willnow be clear'when a layer of plaster such as is applied thereto, it willpossess a hard, strong fibre layer, or surface 78, a soft and yieldingfibre ortion such as 79, and another plaster holding surface 77 which isyielding and may be waterproofed if desired. Further the board beingcomposed of interlaced fibres it is a great deal stronger than priorboards. 1

. I prefer to provide grooves 101 or other indentations in the board togive a better hold to the plaster, which grooves may be convenientlyformed during the making of the board by well known means.

I further prefer to employ bagasse or pith carrying fibres in the makingof this board, for when said fibres constituting the layer 78 are coatedwith the above men:

tioned precipitated compounds that were.

previously dissolved off the fibres, they take on an exceedingly smoothand hard surface, with a minimum of expense; and further when the middlelayer is composed of said bagasse fibres, owing to their pith likeprotuberances they intertangle in such a way as to form a board havingan unusual tensile strength as well as an unusual breaking strength. Afurther advantage of employing bagasse fibres resides in the fact thatby regulating the beating action in the beating engine, I can produceaggregates consisting of a plurality of fibres bound together, whichaggregates on being fed to the channel 40, will constitute the middleresilient layer 79 with relatively very large air spaces, so its heatinsulating properties will be greatly enhanced. due'to these air cells,in addition tothe heat insulation afforded by their natural pith whilenot affecting its yielding nature. This is an important advantage inplaster boards.

It is obvious that those skilled in the art may vary the details of theinvention with- "out departing from the spirit thereof.

Therefore, I do not wish to be limited to the above disclosure except asmay be required by the claims.

\Vhat I claim is 1. The herein described heat insulatingplaster boardcomprising a relatively unyielding hard and strong layer of bagassefibres interlaced with a relatively soft and yielding layer of bagassefibres, all said fibres being associated with their natural pith; and alayer of plaster attached to said board, substantially as described.

2. The herein described heat insulating plaster board comprising arelatively unyielding hard and strong layer of bagasse fibres interlacedwith a relatively soft and yielding layer of bagasse fibres, the latterlayer interlaced with a third layer of water proofed fibres, all saidfibres being associated with their natural pith; and a layer of plasterattached to said board, substantially as described.

3. The herein described plaster board comprising a relatively hard andstrong layer of fibres interlaced with a relatively soft and yieldinglayer of fibres; and said board provided with means to hold plasterthereto, whereby said hard layer affords a strengthening means for theboard, andsaid soft layer affords a means adapted to;

yield as said plaster expands, substantially as described.

4. The herein described plaster board comprising a relatively hard andstrong layer of fibres interlaced with a relatively. soft and yieldinglayer of fibres; said soft layer being provided with depressions toreceive plaster; and an outside layer of fibres interlaced with one ofsaid first men-- tioned fibres and provided with a water proofingmaterial, substantially as described. 5.. The herein described plaster.board comprising a relatively unyielding, hard -layer of pith carryingfibres associated with a waterproofing material interlaced with arelatively yielding, soft layer of fibres; and means associated with oneof said layers to bond plaster thereto, substantially as described.

In testimony whereof I aflix my si JOHN K. S

ature.

